1d mark III or 5d mark II

I have a very tough decision to make. I'm deciding between a 1d mark III or a 5d mark II. I mostly shoot weddings but do some portraits and landscapes as well. I would automatically go for the 5d mark II except I'm used to the 1d body. I would like something lighter and have held the 1d mark III and love it. I picked up the 5d mark II briefly and wasn't wild about it but thought it was o.k. (better than the classic)

I like the 1d mark III because of the better build, better autofocus ( don't have to re-compose) weather sealing and longer life durability.

I like the 5d mark II because primarily it's full-frame and this is something I want the most. It also has a little better high noise ability. I also like that it's lighter so I can go hiking with it and not get tired.

I have a 1dmark IIN and a 20d right now and want to upgrade. The only thing that really bugs me about the 5d mark ii is the auto focus isn't as snappy as the 1d. I guess I would get used to it though if it has much better image quality. Are there 1d users who had a tough time adjusting from the 1d series body to the 5d body? I've heard the 1d mark III has great image quality with high iso as well. I just wish it was full frame.